PURPOSE: To provide the title growth rate accelerator which does not reduce its excellent growth rate accelerating activity even by the combined use with antibiotics, and prevents the diarrhea and white straining of cattle, etc., caused by the overdose of antibiotics.

CONSTITUTION: A growth rate accelerator for cattle and poultry containing lactic acid bacteria resistant to antibiotics (e.g. variant of Streptococcus faecalis, Streptococcus lactis, Bifidobacterium bifidus, Lactobacillus lactis, Lactobacillus acidophilus, etc. resistant to antibiotics and sulfamides, for example, "concenteropolyal powder" containing Streptococcus faecalis BIOW4R as an effective component).